1. Field Of The Invention
This invention relates to airport ground lights for controlling the movement of aircraft. The invention relates more particularly to improvements for enhancing the visibility of airport ground lights.
2. Description Of The Prior Art
Airport ground lights are used to control the movement and placement of aircraft at an airport. Such lights which have predetermined colors associated with a particular control function are used as taxiway lights, landing lights, holding area lights and ramp lights where aircraft may be parked. These lights comprise a luminaire and a support body which both spaces and supports the luminaire above the ground at a predetermined height, generally about up to 14 inches. In many instances the lights are located immediately adjacent to but off a paved surface in a grass or sodded area so as to avoid impact by wheels and struts of aircraft which travel on the paved surface. Such lights are generally made frangible so as to break away when struck by an aircraft in order to avoid and minimize damage to the aircraft.
It is desirable and necessary that these lights be easily viewed from the aircraft by pilots in their cockpits and during the daylight period by airport maintenance personnel. However, in view of the grass and sodded terrain in which the lights are located, foliage often grows about the lights to the height of the lights thus reducing visibility of the lights and indeed at times obstructing viewing of the lights.
In order to maintain the visibility of these lights, it has been the practice to repeatedly mow the grass and sodded area about such light. However, such mowing is generally performed with a relatively large ganged mower which is not readily manuverable at locations relatively close to the lights. Attempts to mow foliage close to the light often results in impacting and dislodging the frangible support and sometime damaging the support. At times the frangible support may even damage the mower blades and the mower itself.
An alternative to mowing the undesired foliage is the spraying of herbicides to suppress or kill the foliage. However, all of the foliage is generally suppressed by this technique resulting in weathering and erosion of the area about the ground light. As a consequence, water ponding and exposure of subsoil occurs and ultimately corrosion of the substructure supporting the light. Jet blast often projects this material about and this is a hazard. Moreover, present day environmental factors tend to discourage the use of herbicides.
Another alternative employed for suppressing foliage around landing lights has been to cover the area about the light with gravel. This functions to suppress foliage growth. However, jet blasts have at times dislodged and blown the gravel about thereby creating a hazard to other aircraft and to personnel in the area.
These prior attempts to suppress the foliage about airport ground lights has been relatively ineffective and has been costly in terms of manpower, equipment and the replacement of damaged lights.